UWorld Pharmacology Practice Test

Sitagliptin is a medication used to manage type 2 diabetes, and it functions as a DPP-4 inhibitor. DPP-4, or dipeptidyl peptidase-4, is an enzyme that breaks down incretin hormones, including GLP-1 (glucagon-like peptide-1). By inhibiting the action of DPP-4, sitagliptin effectively prevents the degradation of GLP-1, leading to increased levels of this hormone in the bloodstream. GLP-1 plays a critical role in glucose metabolism; it enhances insulin secretion from the pancreas in a glucose-dependent manner, suppresses glucagon secretion (which reduces glucose production by the liver), and contributes to feelings of satiety. Therefore, the inhibition of DPP-4 by sitagliptin promotes better glycemic control through sustained activity of GLP-1. Understanding this mechanism highlights the importance of DPP-4 in the context of sitagliptin therapy, as targeting this enzyme enhances the hormone's beneficial effects on blood sugar regulation, improving overall diabetes management.